A concise guide to understanding the many mechanical threads commonly encountered by amateur astronomers.

Whether dealing with telescopes, eyepieces, filters, or focusers, nearly every amateur astronomer is bound to come across a large and sometimes confusing array of machined threads. Sorting out which type of thread is which, and which component fits into another, can make it difficult to find and order the right parts and make sure they all fit together.

I'm trying to connect a 1.25" Altair MG32 guider scope[1] with an illuminated crosshair from agena[2]. unfortunately, both have (natively) the same male thread, and the adapter that comes from the crosshair eyepiece is slightly too small to fit the scope.

I haven't found a female/female adapter anywhere do you know 3D models for the threads so I can print something?